1. Field of the Invention
The present invention relates to an electrophotographic image forming apparatus and an image formation system.
2. Description of Related Art
In general, an electrophotographic image forming apparatus (such as a printer, a copy machine, and a fax machine) is configured to irradiate (expose) a charged photoconductor with (to) laser light based on image data to form an electrostatic latent image on the surface of the photoconductor. The electrostatic latent image is then visualized by supplying toner from a developing device to the photoconductor (image carrier) on which the electrostatic latent image is formed, whereby a toner image is formed. Further, the toner image is directly or indirectly transferred to the sheet, and thereafter fixed through heating and pressing at a fixing nip of a heating member (for example, a fixing roller) and a pressing member (for example, a pressure roller), thereby forming an image on the sheet.
Examples of the sheets used in the above-mentioned image formation system include, in addition to common sheets composed only of paper, a sheet called label sheet which contains paste (adhesive agent) for pasting. Examples of such a label sheet include, in addition to short sheets such as A4-sheets, long sheets of several hundred meters long in one roll (hereinafter referred to as “label roll sheet”).
Conventionally, an image formation system in which a sheet feeding apparatus configured to feed a long sheet is connected on a preceding side of the above-mentioned image forming apparatus, and a winding apparatus configured to wind up the long sheet on which an image is formed by the image forming apparatus is connected on a succeeding side of the above-mentioned image forming apparatus has been practically used as a system suitable for a long sheet such as the label roll sheet.
When a sheet containing paste such as the label sheet is used in the above-mentioned image formation system, paste (adhesive agent) of a sheet end portion may be exuded and attached to a roller or a belt during a pressing operation at a secondary transfer section and a fixing section of the image forming apparatus, and a transfer cleaning section, a secondary transfer roller, or a belt may be smeared, thus causing abnormal abrasion and image defects during a cleaning operation and the like.
Japanese Patent Application Laid-Open No. 6-230727 discloses a method in which paste of a sheet end portion is removed at the time of manufacturing label sheets. Japanese Patent Application Laid-Open No. 6-230727 discloses a method in which both end portions of a label sheet are pressed with a pair of upper and lower press rollers to put out adhesive agent (paste), and thereafter, the part on the end portion side relative to an appropriate position of the pressed portion at the both end portions of the label sheet is disconnected and removed using a pair of upper and lower slitters.
In the conventional method of removing adhesive agent disclosed in Japanese Patent Application Laid-Open No. 6-230727, both end portions of a label sheet are simply pressed with the pressing rollers, and as such adhesive agent may not sufficiently protruded from the sheet end portion. In the above-mentioned method of removing adhesive agent, the sheet end portions are disconnected regardless of whether the adhesive agent is sufficiently protruded, and the adhesive agent is removed together with the corresponding part of the sheet. However, in this case, the disconnected sheet end portion becomes wastes, and as a result operations or components for the wastes are required to be provided. In addition, in the case where change of the sheet area due to disconnection is not allowed, such a method cannot be employed as a matter of course.